Core & Cavity II

This page is number two that discusses the core and cavity functions of Mold Design Advisor. Introduced here are the initial settings of the pull direction and mold block, and part splitting is described.

• Pull Direction and Mold Block
• Part Splitting

Exercises:

• 1. Setting the Pull Direction and Creating the Mold Block
• 2. Splitting the Part

Pull Direction and Mold Block

You can initialize two features in Mold Design Advisor: The default pull direction and the mold block.

While working with mold parts, you need to specify the pull direction for separating the core and the cavity. You can set this as an initial setting in the Core & Cavity menu, which will then be used as the default in subsequent operations that use it. You can always change the direction individually per operation if necessary. As a visual aid, Mold Design Advisor displays a graphical feedback arrow in the viewport that indicates the pull direction: This can be switched off if you wish.

To create the core and cavity of a part, you first need to create a mold block with respect to the pull direction. This action creates a mold assembly into which the part can be moved or copied. You can specify also the following parameters for the mold block: the x-axis direction (which must not be collinear with the pull direction) to orient the block the width, depth and height of the block.

Exercise 1: Setting the Pull Direction and Creating the Mold Block

Note: This exercise "continues" in a sense in the following exercises. Keep your results for further use.

In this exercise, you will set the default pull direction on the part cored in the coring exercise, and create its mold block.

• Load the package TUT90-MDA-coring-ex2.pkg from the Parts directory:
  
  Note: this is the cored part from the coring exercise. If you still have that part loaded, you do not need to load the package above.
• In Mold Design Advisor, open the Pull Direction menu (click Core/Cavity in the main menu, and click Pull Direction).
• Click Pull Direction in the menu, and click X in the Direction 3D tool.
• Click the Visible switch on.
• Click OK.

A red feedback arrow now indicates the pull direction for the part:

• To create the mold block, open the Mold Block menu (click Mold Block in the Core & Cavity menu).
• Change the Copy Part selection to No. By default, the Advisor places a copy of the part in the mold assembly to be created, and keeps the original part in its position in the part structure; however, we need no copy.
• Leave all other options as they are, and click OK.

The mold block is shown in the viewport:

Part Splitting

Mold parts can be split into their core, cavity, silhouette and undercut faces. You can split parts automatically or manually and also check the status of split parts. Special features are created to which the various faces are kept (cavity features, core features, and so on). These can be seen in the Structure browser.

To split a part automatically, you specify the pull direction and one of three modes that determines how silhouette faces are treated:

• None: Collect all silhouette faces but do not move them. You must then specify manually into which part of the form each face is to go.
• To Cavity: Move to the core all regions of silhouette faces that are bounded by core faces only, and move to the cavity those that are bounded by cavity faces only. Move all remaining silhouette faces to the cavity.
• To Core: As To Cavity, but move all remaining silhouette faces to the core.

The following graphics show the differences between the three silhouette face modes. The color-coding is taken from the default color settings for part splitting.

You can also split a part by manually collecting its individual faces and assigning them to the core, cavity or slider. Such form classifications can also be modified later.

One effective method of part splitting is a sort of semi-automatic process: First use the automatic part splitting method, in which the Advisor "predicts" the silhouette face classification, and then modify this classification manually later. In other words, you modify the features created with the automatic part splitting mode.

Finally, you can check if a part has been completely split with the Check Split tool. The tool highlights those faces that are not part of a core or cavity feature.

Exercise 2: Splitting the Part

In this exercise, you will split the part from the previous exercise, first using the To Core method of automatic splitting. Then you will use manual splitting to create four slider features.

• Use the part from the previous exercise (or load the package TUT90-MDA-coring-ex2.pkg from the Parts directory).
• In Mold Design Advisor, open the Autom. Part Splitting menu (click Core/Cavity in the main menu, and click Automatic).
• Select the To Core splitting method from the Mode list.
• Click the Keep Critical Silhouettes switch off. (Be default, critical silhouette edges are imprinted on the part; we don't need these so we shall discard them.)
• Click Preview to see the color-coded classification of the faces.
• Click OK.

Although no change is visible on the part, in fact four plastic features have been created: cavity, core, and two undercut features.

Now create the slider features:

• Open the Manual Part Splitting menu (click Core/Cavity in the main menu, and click Manual).
• From the Type list, select Slider.
• The Direction 3D tool opens. Specify the pull direction of the slider: Click Face Normal and click the face marked with an X below:
  
• Under Add Faces by, click Faces and click the faces that allow a smooth removal of the (first) slider:
  
• Click End in the Select tool, and then click OK.

Repeat the steps above to create the other three slider features: